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3) Float Charge - For extended battery life the Phase Three then automatically
switches to a lower float voltage level. This float charge keeps batteries at peak
condition without overcharging. The charger may be left in this stage for months
without attention (though periodic checks of electrolyte level in flooded batteries is
recommended).
A typical 12 volt, three phase charging cycle is illustrated below.
FIGURE 7: TYPICAL (12V) CHARGER OUTPUT GRAPH
(INTO BATTERY WITHOUT LOAD)
Up to 8-10 hours**
*
* =Actual charge and float voltages depend upon gel-cell/lead acid settings and/or
temperature compensation function.
** =As required by battery state of charge with an 8-10 hour maximum. Length of
maximum bulk/absorption phase duration may be increased/decreased by installer
adjustment at time of installation.
†=Intermittent loads
B) Time-Out Circuit
Batteries have a tendency to lose their electrolyte and may be damaged if they are
maintained for long periods of time in the elevated voltage of the absorption phase.
Therefore, the Phase Three Charger employs a special time-out circuit. This circuit
is initialized each time a.c. is first applied to the charger (or when the re-initialize
button on the optional remote panel is activated) and runs for a pre-set interval
before forcing the charger to go into the float (lower voltage) mode. The functioning
of the charger during this interval is as follows:
If the current demand of the batteries/load falls below 5-15 percent of the charger's
output capacity prior to the circuit timing-out, the charger will automatically switch
to the float mode. (For instance, with model PT-40CE, the charger will drop into
float mode at about 2-6 amps output.) If demand rises to about 10-20 percent of
capacity (4-8 amps with PT-40CE, for instance), the charger will return to the elevated
output of the absorption phase. This switching back and forth between modes may
occur until the circuit times-out (8-10 hours after a.c. is first applied), after which the
†
†
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charger will remain at float voltage, until the circuit is re-initialized, either by turning
the charger off and then on again or by pressing the re-initialize button on the optional
remote panel.
Note: The PT-CE charger is able to deliver its full rated output current while in
the float mode.
Installation Note: The time-out circuit of the PT-CE charger has been set at about 8-
10 hours, which is appropriate for battery systems within the capacity range specified
on the front panel of the charger. If the charger is used with a battery system with a
capacity near (or outside) the upper or lower ranges of the specified range of the
charger, adjustment of the time-out circuit may be recommended. If the installer
wishes to make this adjustment at the time of installation, the procedure is as follows
(Caution: Ensure a.c. input has been disconnected before proceeding):
†
1) Remove the four screws on the front panel and three screws on each side of the
unit.
2) Remove the front cover and locate the potentiometer on the small "charger
function" plug-in printed circuit board which is labeled "TIMER ADJ."
3) Using a small flat tip screwdriver, turn the potentiometer clockwise to increase
the amount of time the charger remains in the absorption mode before timing out, or
counterclockwise to decrease the amount of time. The approximate ranges are
illustrated below.
FIGURE 8: ADJUSTING THE TIME-OUT CIRCUIT
Note: Once the time-out circuit has put the charger into float mode, the charger
will remain in this mode. Since the Phase Three Charger is well regulated, it is
able to deliver its full rated output current in this mode and battery discharge
will not occur (provided load current does not exceed charger rating and output
wiring is properly sized).
C) Gel-Cell / Lead Acid Selector Switch
According to most battery manufacturers, the ideal charge regimen for gel-cell and
wet or flooded lead acid batteries differs somewhat.
The gelled electrolyte in a sealed battery may be lost or damaged by high voltage
and, once lost, cannot be replaced as it can with a wet lead acid battery.
Manufacturers of gel-cells usually recommend an ideal charge voltage which is
slightly lower for a gel-cell than a lead acid battery.
However, when the charger is in the float voltage mode over lengthier periods of
time, gelled electrolyte in a sealed battery is not susceptible to evaporation, as is
the non-immobilized electrolyte of a wet lead acid battery. This evaporation can be
8-10 Hours
5-7 Hours
11-13 Hours
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